1. Field of the Invention
The present indention relates to an apparatus of heating semiconductors.
2. Description of Related Art
In a system of producing semiconductors used far dry process or plasma coating in semiconductor production, it has been used halogen-based plasma such as F, Cl or the like Easing high reactivity for etching or cleaning. It is thus required, for a member equipped to suck semiconductor production system, high corrosion resistance, so that it has been generally used a member of an anti-corrosive metal such as aluminum with alumite treatment, HASTELLOY or the like or a ceramic material. Especially, it is necessary high corrosion resistance and low particle generation properties for an electrostatic chuck or heater member supporting and fixing a Si wafer, so that it has bees used a high corrosion resistant ceramic member such as aluminum nitride, alumina, sapphire or the like. As these materials are used for a long time, they are gradually corroded to induce particle generation, so that it has been demanded a material whose corrosion resistance is further improved. For attending such demands, it is studied to use, as the material, magnesia, spinel (MgAl2O4) or a composite material thereof whose corrosion resistance is higher than that of alumina (For example, Patent document 1: U.S. Pat. No. 3,559,426B).
It is further known a ceramic heater used for heating wafers. In such ceramic heaters, temperature uniformity of the heater is required for heating the wafer uniformly. For example, according to the disclosure of Patent Document 2 (Patent Publication No. H08-073280A), a heat resistance is embedded in an aluminum nitride based ceramic plate, to which an aluminum nitride based shaft is bonded to provide a ceramic heater. According to the descriptions of Patent document 3 (Patent Publication No. 2003-288975A), in a ceramic heater with a shaft, a content of metal carbide in a heat resistance is lowered to reduce the deviation of the carbide content in the heat resistance depending on the positions, so that the temperature distribution on its heating face is reduced.